1.3. Migrating Data Warehouse to a Separate Machine

Migrate the Data Warehouse service from the Red Hat Virtualization Manager to a separate machine. Hosting the Data Warehouse service on a separate machine reduces the load on each individual machine, and allows each service to avoid potential conflicts caused by sharing CPU and memory with other processes.

Migrate the Data Warehouse service and connect it with the existing ovirt_engine_history database, or optionally migrate the ovirt_engine_history database to a new database machine before migrating the Data Warehouse service. If the ovirt_engine_history database is hosted on the Manager, migrating the database in addition to the Data Warehouse service further reduces the competition for resources on the Manager machine. You can migrate the database to the same machine onto which you will migrate the Data Warehouse service, or to a machine that is separate from both the Manager machine and the new Data Warehouse service machine.

1.3.1. Migrating the Data Warehouse Database to a Separate Machine

Optionally migrate the ovirt_engine_history database before you migrate the Data Warehouse service. Use engine-backup to create a database backup and restore it on the new database machine. For more information on engine-backup, run engine-backup --help.

Attach the required subscriptions to your system. See Enabling the Red Hat Virtualization Manager Repositories in the Installation Guide.

To migrate the Data Warehouse service only, see Section 1.3.2, “Migrating the Data Warehouse Service to a Separate Machine”.

Migrating the Data Warehouse Database to a Separate Machine

  1. Create a backup of the Data Warehouse database and configuration files:

    # engine-backup --mode=backup --scope=dwhdb --scope=files --file=file_name --log=log_file_name
  2. Copy the backup file from the Manager to the new machine:

    # scp /tmp/file_name root@new.dwh.server.com:/tmp
  3. Install engine-backup on the new machine:

    # yum install ovirt-engine-tools-backup
  4. Restore the Data Warehouse database on the new machine. file_name is the backup file copied from the Manager.

    # engine-backup --mode=restore --scope=files --scope=dwhdb --file=file_name --log=log_file_name --provision-dwh-db --no-restore-permissions
  5. The Data Warehouse database is now hosted on a separate machine from that on which the Manager is hosted. Proceed to Section 1.3.2, “Migrating the Data Warehouse Service to a Separate Machine” to complete the migration.

1.3.2. Migrating the Data Warehouse Service to a Separate Machine

Migrate a Data Warehouse service that was installed and configured on the Red Hat Virtualization Manager to a dedicated host machine. Hosting the Data Warehouse service on a separate machine helps to reduce the load on the Manager machine. Note that this procedure migrates the Data Warehouse service only; to migrate the Data Warehouse database (also known as the ovirt_engine_history database) prior to migrating the Data Warehouse service, see Section 1.3.1, “Migrating the Data Warehouse Database to a Separate Machine”.

Prerequisites

Ensure that you have completed the following prerequisites:

  1. You must have installed and configured the Manager and Data Warehouse on the same machine.
  2. To set up the new Data Warehouse machine, you must have the following:

    • A virtual or physical machine with Red Hat Enterprise Linux 7 installed.
    • Attached the Red Hat Enterprise Linux Server and Red Hat Virtualization subscriptions.
    • The password from the Manager’s /etc/ovirt-engine/engine.conf.d/10-setup-database.conf file.
    • Allowed access from the Data Warehouse machine to the Manager database machine’s TCP port 5432.
    • The ovirt_engine_history database credentials from the Manager’s /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf file. If you migrated the ovirt_engine_history database using Section 1.3.1, “Migrating the Data Warehouse Database to a Separate Machine”, retrieve the credentials you defined during the database setup on that machine.

Installing this scenario requires four steps:

1.3.2.1. Setting up the New Data Warehouse Machine

  1. Attach the required subscriptions to your system. See link: Enabling the Red Hat Virtualization Manager Repositories in the Installation Guide for more information.
  2. Ensure that all packages currently installed are up to date:

    # yum update
  3. Install the ovirt-engine-dwh-setup package:

    # yum install ovirt-engine-dwh-setup

1.3.2.2. Stopping the Data Warehouse Service on the Manager Machine

  1. Stop the Data Warehouse service:

    # systemctl stop ovirt-engine-dwhd.service
  2. If the database is hosted on a remote machine, you must manually grant access by editing the postgres.conf file. Edit the /var/lib/pgsql/data/postgresql.conf file and modify the listen_addresses line so that it matches the following:

    listen_addresses = '*'

    If the line does not exist or has been commented out, add it manually.

    If the database is hosted on the Manager machine and was configured during a clean setup of the Red Hat Virtualization Manager, access is granted by default.

    See Section 1.3.1, “Migrating the Data Warehouse Database to a Separate Machine” for more information on how to configure and migrate the Data Warehouse database.

  3. Restart the postgresql service:

    # systemctl rh-postgresql95-postgresql restart

1.3.2.3. Configuring the New Data Warehouse Machine

The questions shown in this step only appear if you are migrating the ovirt_engine_history database to one machine and Data Warehouse service to a different machine. The order of the questions may differ depending on your environment.

  1. If you are migrating both the ovirt_engine_history database and the Data Warehouse service to the same machine, run the following, otherwise proceed to the next step.

    # sed -i '/^ENGINE_DB_/d' \
            /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf
    
    # sed -i \
         -e 's;^\(OVESETUP_ENGINE_CORE/enable=bool\):True;\1:False;' \
         -e '/^OVESETUP_CONFIG\/fqdn/d' \
         /etc/ovirt-engine-setup.conf.d/20-setup-ovirt-post.conf
  2. Run the engine-setup command to begin configuration of Data Warehouse on the machine:

    # engine-setup
  3. Press Enter to configure Data Warehouse:

    Configure Data Warehouse on this host (Yes, No) [Yes]:
  4. Press Enter to accept the automatically detected host name, or enter an alternative host name and press Enter:

    Host fully qualified DNS name of this server [autodetected host name]:
  5. Press Enter to automatically configure the firewall, or type No and press Enter to maintain existing settings:

    Setup can automatically configure the firewall on this system.
    Note: automatic configuration of the firewall may overwrite current settings.
    Do you want Setup to configure the firewall? (Yes, No) [Yes]:

    If you choose to automatically configure the firewall, and no firewall managers are active, you are prompted to select your chosen firewall manager from a list of supported options. Type the name of the firewall manager and press Enter. This applies even in cases where only one option is listed.

  6. Enter the fully qualified domain name and password for the Manager. Press Enter to accept the default values in each other field:

    Host fully qualified DNS name of the engine server []: engine-fqdn
    Setup needs to do some actions on the remote engine server. Either automatically, using ssh as root to access it, or you will be prompted to manually perform each such action.
    Please choose one of the following:
    1 - Access remote engine server using ssh as root
    2 - Perform each action manually, use files to copy content around
    (1, 2) [1]:
    ssh port on remote engine server [22]:
    root password on remote engine server engine-fqdn: password
  7. Answer the following question about the location of the ovirt_engine_history database:

    Where is the DWH database located? (Local, Remote) [Local]: Remote

    Type the alternative option as shown above then press Enter.

  8. Enter the fully qualified domain name and password for your ovirt_engine_history host. Press Enter to accept the default values in each other field:

    DWH database host []: dwh-db-fqdn
    DWH database port [5432]:
    DWH database secured connection (Yes, No) [No]:
    DWH database name [ovirt_engine_history]:
    DWH database user [ovirt_engine_history]:
    DWH database password: password

    See Section 1.3.1, “Migrating the Data Warehouse Database to a Separate Machine” for more information on how to configure and migrate the Data Warehouse database.

  9. Enter the fully qualified domain name and password for the Manager database machine. Press Enter to accept the default values in each other field:

    Engine database host []: engine-db-fqdn
    Engine database port [5432]:
    Engine database secured connection (Yes, No) [No]:
    Engine database name [engine]:
    Engine database user [engine]:
    Engine database password: password
  10. Choose how long Data Warehouse will retain collected data::

    Please choose Data Warehouse sampling scale:
    	(1) Basic
    	(2) Full
    	(1, 2)[1]:

    Full uses the default values for the data storage settings listed in Section 2.4, “Application Settings for the Data Warehouse service in ovirt-engine-dwhd.conf” (recommended when Data Warehouse is installed on a remote host).

    Note

    If you migrate from <literal>Basic</literal> to <literal>Full</literal>, initially only the existing basic data will be available.

    Basic reduces the values of DWH_TABLES_KEEP_HOURLY to 720 and DWH_TABLES_KEEP_DAILY to `0, easing the load on the Manager machine but with a less detailed history.

  11. Confirm that you want to permanently disconnect the existing Data Warehouse service from the Manager:

    Do you want to permanently disconnect this DWH from the engine? (Yes, No) [Yes]:
  12. Confirm your installation settings:

    Please confirm installation settings (OK, Cancel) [OK]:

1.3.2.4. Disabling the Data Warehouse Package on the Manager Machine

  1. On the Manager machine, restart the Manager:

    # service ovirt-engine restart
  2. Disable the Data Warehouse service:

    # systemctl disable ovirt-engine-dwhd.service
  3. Remove the Data Warehouse files:

    # rm -f /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/* .conf /var/lib/ovirt-engine-dwh/backups/*

The Data Warehouse service is now hosted on a separate machine from that on which the Manager is hosted.